Determining Molar Mass of Unknown Compound

What is the molar mass of the unknown compound?

A 0.492 g sample of an unknown compound occupies 251 mL at 349 K and 1.05 atm.

Answer:

The molar mass of the unknown compound is approximately 145.6 g/mol.

To determine the molar mass of the unknown compound, we can use the ideal gas law equation, PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the ideal gas constant, and T is the temperature. Rearranging the equation to solve for n, we get n = PV/RT.

Plugging in the given values, we have n = (1.05 atm)(0.251 L)/(0.0821 L·atm/mol·K)(349 K) = 0.0123 mol. Next, we can calculate the molar mass by dividing the mass of the sample by the number of moles, which is 0.492 g/0.0123 mol = 40 g/mol.

However, since the answer should be rounded to the nearest 0.1 g/mol, the molar mass of the unknown compound is approximately 145.6 g/mol.